Your skin has been encountering lactic acid since before you were born. It's present in breast milk, forms naturally on skin as part of its protective acid mantle, and has been used in beauty rituals for thousands of years. When Egyptian queens bathed in milk, they were applying lactic acid—they just didn't have a name for the compound doing the work.
This history matters because lactic acid isn't some laboratory creation your skin has never seen. It's a molecule your body recognizes, works with naturally, and responds to differently than synthetic alternatives. Understanding what lactic acid actually is—and what makes it distinct from other exfoliants—helps explain why it works so well for skin types that struggle with conventional acids.
The Chemistry Made Simple
Lactic acid belongs to a family called alpha-hydroxy acids, or AHAs. These are naturally occurring organic acids found in various foods and substances: glycolic acid in sugar cane, malic acid in apples, citric acid in citrus fruits, and lactic acid in fermented milk products.
What defines an AHA is its molecular structure—specifically, a hydroxyl group attached to the carbon atom adjacent to the carboxylic acid group. This structure gives AHAs their ability to loosen the bonds between dead skin cells, allowing them to shed more easily. It's gentle chemical exfoliation rather than physical scrubbing.
Among the AHAs, lactic acid has a molecular weight of 90.08 g/mol, making it larger than glycolic acid (76.05 g/mol) but smaller than some other AHAs. This size matters enormously for how the acid behaves on skin. Larger molecules penetrate more slowly and work more superficially, which generally translates to less irritation and a gentler exfoliating action.
What Lactic Acid Does for Skin
The primary function of lactic acid in skincare is exfoliation—but it accomplishes this through a different mechanism than physical scrubs or enzyme treatments.
Lactic acid works by disrupting the connections between corneocytes, the flat, dead skin cells that make up the outermost layer of your skin (the stratum corneum). These cells are held together by protein structures called desmosomes and a lipid-rich "mortar" that keeps your skin barrier intact. As we age, or when skin is stressed, this shedding process slows down, leading to dull skin, rough texture, and clogged pores.
Lactic acid accelerates this natural shedding by weakening the bonds that hold dead cells in place. The cells release more easily, revealing fresher skin beneath and allowing better penetration of other skincare products.
But lactic acid does more than just exfoliate. It also functions as a humectant, meaning it attracts and holds water in the skin. This dual action—exfoliating while hydrating—sets lactic acid apart from most other exfoliating acids, which can leave skin feeling tight and dry.
Research also suggests that lactic acid stimulates the production of ceramides, the lipid molecules essential for skin barrier function. This means that while lactic acid is removing dead surface cells, it's simultaneously supporting the structures that keep your skin protected and hydrated.
Natural Sources vs. Synthetic Forms
Lactic acid can be produced in several ways. Synthetic lactic acid is manufactured through chemical synthesis. Fermentation-derived lactic acid comes from bacterial fermentation of sugars. And naturally occurring lactic acid exists within whole foods and substances—most notably, fermented milk products.
The molecular structure is identical regardless of source. A lactic acid molecule from a laboratory is chemically indistinguishable from one produced by Lactobacillus bacteria in goat milk. So why does the source matter?
Context. When you apply synthetic lactic acid, you're getting an isolated compound at a specific concentration, formulated at a particular pH, with whatever other ingredients the formulator chose to include. When you apply fresh goat milk, you're getting lactic acid within a complex matrix of fats, proteins, vitamins, and other compounds that modify how your skin experiences the acid.
On our Washington State farm, we use fresh, non-reconstituted goat milk as a primary ingredient precisely because of this matrix effect. The lactic acid arrives surrounded by natural buffers and supportive nutrients—not as an isolated compound your skin has to manage alone.
The pH Factor
For lactic acid to exfoliate effectively, it needs to be at a certain pH level. In highly alkaline environments, lactic acid becomes neutralized and loses its exfoliating activity. In very acidic environments, it becomes more aggressive.
Most synthetic lactic acid products are formulated at pH levels between 3.0 and 4.0 to ensure the acid remains in its free (active) form. This is significantly more acidic than healthy skin's natural pH of around 5.5.
Fresh goat milk has a pH of approximately 6.3-6.7, which is closer to skin's natural pH. The lactic acid in goat milk exists in a different equilibrium than in synthetic formulations—less of it is in its free, active form at any given moment, which contributes to the gentler action that many people experience.
This isn't necessarily better or worse than synthetic formulations. It's different. For people whose skin tolerates concentrated acids well, synthetic products may deliver faster results. For people whose skin reacts to aggressive formulations—and that's a significant portion of the population—the naturally buffered lactic acid in goat milk offers benefits without the inflammatory response.
Who Benefits Most From Lactic Acid
Lactic acid's unique properties make it particularly suited to certain skin types and concerns.
Dry skin responds well to lactic acid because of its humectant properties. Unlike some exfoliants that leave skin feeling stripped, lactic acid helps skin retain moisture while removing dead cell buildup.
Sensitive skin often tolerates lactic acid better than glycolic acid or other smaller-molecule AHAs. The gentler penetration and natural buffering in goat milk formulations make it accessible to people who've given up on chemical exfoliation entirely.
Mature skin benefits from lactic acid's ability to stimulate ceramide production and support cell turnover. As skin ages, its natural renewal process slows, and gentle encouragement from lactic acid can help maintain a fresher, more radiant appearance.
Skin with texture concerns—roughness, uneven tone, mild keratosis pilaris—often sees improvement with consistent lactic acid use. By supporting the natural shedding process, lactic acid helps reveal smoother skin over time.
The Artisan Approach
Every Artisan product contains fresh goat milk from our own herd, which means every product delivers naturally occurring lactic acid in its native context. Combined with MSM in every formula—which provides anti-inflammatory support—and other nourishing ingredients, our products offer gentle exfoliation without the compromises that many people accept as normal with conventional AHA products.
This isn't about lactic acid being magic. It's about delivery. The same compound, presented to skin in a supportive matrix rather than as an isolated chemical, produces a different experience. For many people, that difference means finally being able to enjoy the benefits of exfoliation without the redness, burning, and irritation they've learned to expect.
